The present invention relates to a fuel injection system for direct injection of fuel into the combustion chamber(s) of an internal combustion engine.
The present invention is based on a fuel injection system. Unexamined Japanese Published Patent Application No. 08-312503 describes mounting holes for one fuel injector, in which each mounting hole may be provided on the cylinder head of an internal combustion engine, with one spray section of the fuel injector inserted into each hole. The fuel injector is held down by a hold-down device designed as a tightening bracket against the relatively high combustion pressure prevailing in the combustion chamber. A fuel distributor line connecting the fuel injectors to a fuel pump supplies fuel to the fuel inlet orifices provided on the fuel injectors. The fuel distributor line has one fuel outlet orifice for each fuel injector. To achieve the required seal, a sealing element in the form of an O-ring is provided for each.
However, one disadvantage of this known assembly method is that each fuel injector must be installed individually on the cylinder head, thus resulting in a very complicated assembly operation involving multiple steps. It is impossible to pretest the fuel injection system for leakage, for example. A fully automatic manufacturing process is made difficult due to the multiple operations.
Furthermore, it is also a disadvantage that the fuel distributor line and the hold-down device of the fuel injectors are mounted in the respective mounting holes in the cylinder head through separate elements. Therefore, the fuel injectors must first be preassembled in the mounting holes before the fuel distributor line can be positioned and attached to the cylinder head. Therefore, this known type of assembly has a relatively low degree of integration and the procedure is complicated.
German Published Patent Application No. 29 08 095 describes a fuel injector not provided for direct injection of fuel can be mounted on a fuel that distributor line by a retaining strap. Also described is an inlet section of the fuel injector that can be inserted into the fuel distributor line by a nipple connector. However, a hold-down force that can withstand the combustion pressure of the internal combustion engine cannot be transmitted over the retaining strap to the fuel injectors, so this type of assembly is unsuitable for fuel injectors for direct injection of fuel into the combustion chamber of an internal combustion engine.
Essentially, it is described in European Published Patent Application No. 0 491,582 that fuel injectors can be preassembled on a fuel distributor line before being inserted into the mounting holes. However, this known fuel injection system is also unsuitable for direct injection of fuel into the combustion chamber of an internal combustion engine, but instead it is suitable for indirect injection of fuel into the intake manifold of the internal combustion engine. The retaining elements are also unsuitable for transmitting an adequate hold-down force for withstanding the combustion pressure of the internal combustion engine, so this type of assembly is also unsuitable for a fuel injection system for direct injection of fuel into the combustion chamber of an internal combustion engine.